Internet Engineering Task force                           Gabor Bajko 
Internet Draft                                                  Nokia 
Intended Status: Proposed Standard                          Subir Das 
Expires: August 27, 2009                       Telcordia Technologies
                                                    February 27, 2009  
 

Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Options for 
                    IEEE 802.21 Mobility Services (MoS) Discovery 
                    draft-ietf-mipshop-mos-dhcp-options-11 

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   document authors. All rights reserved.
   
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Abstract 
    
   This document defines new Dynamic Host Configuration Protocol  
   (DHCPv4 and DHCPv6) options that contain a list IP addresses and a
   list of domain names that can be mapped to servers providing IEEE
  
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Mobility Services DHCP Options                         February 2009 

   802.21 type of Mobility Service (MoS)[MSFD]. These Mobility 
   Services are used to assist an MN in handover preparation (network 
   discovery) and handover decision (network selection). The services 
   addressed in this document are the Media Independent Handover 
   Services defined in [IEEE802.21].  
        
    
 (1) Conventions used in this document 
    
   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in 
   this document are to be interpreted as described in RFC-2119. 
    
 (2) Terminology and abbreviations used in this document 
    
   Mobility Services: a set of different services provided by the 
   network to mobile nodes to facilitate handover preparation 
   and handover decision. In this document, Mobility Services refer to
   the services defined in IEEE 802.21 specifications [IEEE802.21]
    
   Mobility Server: a network node providing Mobility Support Services. 
    
   MIH: Media Independent Handover, as defined in [IEEE802.21]. 
    
   MIH Service: IS, ES or CS type of service, as defined in 
   [IEEE802.21]  
 
Table of Contents 
    
   1. Introduction .................................................2 
   2. MoS IPv4 address option for DHCPv4............................3 
   3. MoS Domain Name List option for DHCPv4........................5      
   4. MoS IPv6 address option for DHCPv6............................7     
   5. MoS Domain Name List option for DHCPv6........................9    
   6. Option Usage.................................................10 
        6.1 Usage of MoS Options for DHCPv4........................10 
        6.2 Usage of MoS Options for DHCPv6........................11 
   7. Security Considerations .....................................12 
   8. IANA Considerations .........................................12 
   9. Acknowledgements ............................................13 
   10. References .................................................13 
       10.1 Normative References ..................................13
       10.2 Informative References ................................13 
   Author's Addresses .............................................14 
   



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1. Introduction 
    
   IEEE 802.21 [IEEE802.21] defines three distinct service types to 
   facilitate link layer handovers across heterogeneous technologies: 
    
   a) Information Services (IS) 
        IS provides a unified framework to the higher layer entities 
   across the heterogeneous network environment to facilitate 
   discovery and selection of multiple types of networks existing 
   within a geographical area, with the objective to help the higher 
   layer mobility protocols to acquire a global view of heterogeneous 
   networks and perform seamless handover across these networks. 

     b) Event Services (ES) 
        Events may indicate changes in state and transmission behavior
   of the physical, data link and logical link layers, or predict state 
   changes of these layers. The Event Service may also be used to 
   indicate management actions or command status on the part of the 
   network or some management entity. 
    
   c) Command Services (CS) 
        The command service enables higher layers to control the 
   physical, data link, and logical link layers. The higher layers may 
   control the reconfiguration or selection of an appropriate link 
   through a set of handover commands. 
    
   In IEEE terminology these services are called Media Independent 
   Handover (MIH) services. While these services may be co-located, 
   the different pattern and type of information they provide does not 
   necessitate the co-location. 
    
   An MN may make use of any of these MIH service types separately or 
   any combination of them [MSFD]. In practice a Mobility Server may 
   not necessarily host all three of these MIH services together, thus 
   there is a need to discover the MIH services types separately. 
    
   This document defines new DHCPv4 and DHCPv6 options and sub-options
   called the MoS IP Address and Domain Name List Options, which allow
   the MN to locate a Mobility Server which hosts the desired service
   type (i.e. IS, ES or CS) as defined in [IEEE802.21]. Apart from 
   manual configuration, this is one of the possible solutions for 
   locating a server providing Mobility Services.  
    
2. MoS IPv4 Address Option for DHCPv4
    
   This section describes the MoS IPv4 Address Option for DHCPv4. 
   Whether the MN receives an MoS address from local or home network 
   will depend on the actual network deployment [MSFD]. The MoS IPv4
  

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   Address Option begins with a option code followed by a length and 
   sub-options. The value of the length octet does not include itself 
   or the option code. The option layout is depicted below:

     0  1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
                                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
                                     | Option Code   |    Length     | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                     Sub-Option 1                              |
     .                                                               . 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       ...                                     |
     .                                                               . 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                     Sub-Option n                              | 
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 
         Option Code 
    
                OPTION-IPv4_Address-MoS (To Be Assigned) - 1 byte  
    
         Length 
    	
                An 8-bit field indicating the length of the option  
                excluding the 'Option Code' and the 'Length' fields 

         Sub-options 
    
                A series of DHCPv4 sub-options 

   When the total length of a MoS IPv4 Address Option exceeds 254 
   octets, the procedure outlined in [RFC3396] MUST be employed to 
   split the option into multiple, smaller options.

   A sub-option begins with a sub-option code followed by a length 
   and one or more IPv4 addresses.  The sub-option layout is 
   depicted below:

       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      | Sub-opt Code  |    Length     |    IP Address . . . . . 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      .                                                               . 
      .                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  
 

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 The sub-option Codes are summarized below.
      +--------------+---------------+
      |  Sub-opt     | Service       |                               
      |   Code*      | Name          |                                            
      +==============+===============+
      |    1         |   IS          |     
      +--------------+---------------+
      |    2         |   CS          | 
      +--------------+---------------+
      |    3         |   ES          | 
      +--------------+---------------+      

*Note: The values `0` '4' to '255' are reserved and MUST NOT be used. 
 
If the length is followed by a list of IPv4 addresses indicating 
appropriate MIH servers available to the MN, servers MUST be listed in
order of preference. Its minimum length is 4, and the length MUST be a
multiple of 4. The sub-option has the following format: 
   
           Code Len   IPv4 Address 1    IPv4 Address 2 
         +-----+---+---+----+----+----+----+----+--- 
         |1..3 | n |a1 | a2 |a3  | a4 | a1 |  ... 
         +-----+---+---+----+----+----+-----+----+-- 
 
     
 
3. MoS Domain Name List Option for DHCPv4 
    
   This section describes the MoS Domain Name List Option for DHCPv4. 
   The general format of this option is depicted below:
  
     0  1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
                                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
                                     | Option Code   |    Length     | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                     Sub-Option 1                              |
     .                                                               . 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       ...                                     |
     .                                                               . 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                     Sub-Option n                              | 
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    Option Code 
    
                OPTION-IPv4_FQDN-MoS (To Be Assigned) - 1 byte  
    
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     Length 	
                An 8-bit field indicating the length of the option  
                excluding the 'Option Code' and the 'Length' fields 

         Sub-options 
    
                A series of DHCPv4 sub-options. 

   When the total length of a MoS Domain Name List Option exceeds 254 
   octets, the procedure outlined in [RFC3396] MUST be employed to 
   split the option into multiple, smaller options.

   A sub-option begins with a sub-option Code followed by a length 
   and one or more FQDNs.  The sub-option layout is depicted below:

       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      | Sub-opt Code  |    Length     |  FQDN(s) . . . . . .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      .                                                               . 
      .                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The sub-option Codes are summarized below.
      +--------------+---------------+
      |  Sub-opt     | Service       |                               
      |   Code*      | Name          |                                            
      +==============+===============+
      |    1         |   IS          |     
      +--------------+---------------+
      |    2         |   CS          | 
      +--------------+---------------+
      |    3         |   ES          | 
      +--------------+---------------+      

*Note: The values `0` '4' to '255' are reserved and MUST NOT be used. 

Thus the sub-option for this encoding has the following format: 

           Code  Len   DNS name of MoS server 
         +-----+----+----+-----+-----+-----+-----+-- 
         |1..3 | n  | s1 |  s2 |  s3 |  s4 | s5  |  ... 
         +-----+----+----+-----+-----+-----+-----+-- 

 
   The Sub-option begins with a sub-option code followed by a length 
   and a sequence of labels that are encoded according to Section 8 of 
   [RFC3315]. 


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   [RFC1035] encoding was chosen to accommodate future international-
   lized domain name mechanisms. The minimum length for this encoding 
   is 3. 
  
   The Sub-option MAY contain multiple domain names, but these should 
   Refer to the NAPTR records of different providers, rather than 
   different A records within the same provider. That is, the use of 
   multiple domain names is not meant to replace NAPTR and SRV records,
   but rather to allow a single DHCP server to indicate MIH servers 
   operated by multiple providers.

   The client MUST try the records in the order listed, applying the
   mechanism described in [MoS-DNS] for each. The client only resolves 
   the subsequent domain names if attempts to contact the first one 
   failed or yielded no common transport protocols between the MN and 
   the server. 
 
   As an example, consider the case where the server wants to offer 
   two MIH IS servers, "example.com" and "example.net".  These would 
   be encoded as follows:  
   +-----+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 
   |1..3 |26 | 7 |'e'|'x'|'a'|'m'|'p'|'l'|'e'| 3 |'c'|'o'|'m'| 0 | 
   +-----+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 
   +---+---+---+---+---+---+---+---+---+---+---+---+---+ 
   | 7 |'e'|'x'|'a'|'m'|'p'|'l'|'e'| 3 |'n'|'e'|'t'| 0 | 
   +---+---+---+---+---+---+---+---+---+---+---+---+---+ 


4. MoS IPv6 Address Option for DHCPv6 
    
   This section describes the MoS IPv6 Address Option for DHCPv6. 
   Whether the MN receives an MoS address from local or home network 
   will depend on the actual network deployment [MSFD]. The MoS 
   Discovery Option begins with a option code followed by a length 
   and sub-options. The value of the length octet does not include 
   itself or the option code. The option layout is depicted below:

     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |       Option Code             |           Length              | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                     Sub-Option 1                              | 
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   



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     |                       ...                                     |
     .                                                               . 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                     Sub-Option n                              | 
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  
       Option Code 
    
             OPTION-IPv6_Address-MoS (To Be Assigned) - 2 bytes  
  
       Length 
   
             A 16-bit field indicating the length of the option  
             excluding the 'Option Code' and the 'Length' fields.    

       Sub-options 
    
             A series of DHCPv6 sub-options 
                
   The sub-options follow the same format (except the Sub-opt Code and  
   Length value) as described in Section 2. The value of the Sub-opt 
   Code and Length are 2-octets and the Length does not include itself 
   or the Sub-opt Code field. The sub-option layout is depicted below: 

      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     | sub-opt Code                  |     Length                    | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                   IP Address                                  |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      
  The sub-option Codes are summarized below.
      +----------------+---------------+
      |  Sub-opt Code* | Service Name  |                               
      +================+===============+
      |    1           |   IS          |
      +----------------+---------------+
      |    2           |   CS          | 
      +----------------+---------------+
      |    3           |   ES          | 
      +----------------+---------------+
*Note: The values `0` '4' to '65535' are reserved and MUST NOT be 
used. 




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 5. MoS Domain Name List option for DHCPv6    

   This section describes the MoS Domain List Option for DHCPv6. The 
   general format of this option for is depicted below: 
 
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |       Option Code             |           Length              | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                     Sub-Option 1                               | 
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                       ...                                     |
     .                                                               .                                                                                                                        
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     |                     Sub-Option n                              | 
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  
       Option Code 
    
             OPTION-IPv6_FQDN-MoS (To Be Assigned) - 2 bytes  
  
       Length 
   
             A 16-bit field indicating the length of the option  
             excluding the 'Option Code' and the 'Length' fields.    

       Sub-options 
    
             A series of DHCPv6 sub-options 
                
   The Sub-options follow the same format (except the Sub-opt Code and  
   Length value) as described in Section 3. The value of the Sub-opt 
   Code and Length are 2-octets and the Length does not include itself 
   or the Sub-opt Code field. The sub-option layout is depicted below: 

      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
     | sub-opt Code                  |     Length                    | 
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                   FQDN(s)                                     |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 







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  The sub-option Codes are summarized below.
      +----------------+---------------+
      |  Sub-opt Code* | Service Name  |                               
      +================+===============+
      |    1           |   IS          |
      +----------------+---------------+
      |    2           |   CS          | 
      +----------------+---------------+
      |    3           |   ES          | 
      +----------------+---------------+
  *Note: The values `0` '4' to '65535' are reserved and MUST NOT be 
   used. 

   The semantics and content of the DHCPv6 encoding of this option are
   exactly the same as the encoding described in Section 3, except the  
   Option Code and Length value.
      

                 
6. Option Usage 
    
6.1 Usage of MoS Options for DHCPv4 
     
   The requesting and sending of the proposed DHCPv4 options follow the 
   rules for DHCP options in [RFC2131]. 
     
6.1.1 Mobile Node behavior 
    
   The mobile node may perform a MoS discovery either during initial 
   association with a network or when the mobility service is required. 
   It may also try to perform the MoS discovery when it lacks the 
   network information for MoS or needs to change the MoS for some 
   reasons, for instance, to recover from the single point of failure 
   of the existing MoS.  
    
   In order to discover the IP address or domain name of a MoS Server,
   the mobile node(DHCP client) MUST include either a MoS IPv4 Address
   Option or a MoS Domain Name List Option into either a DHCPDISCOVER 
   or DHCPINFORM message. The inserted options MUST include one or more
   sub-option(s) with the Sub-opt Code(s) that represents the service(s)
   the mobile node is interested in. 

6.1.2 DHCP Server behavior 
    
   When the DHCP server receives either a DHCPDISCOVER or DHCPINFORM
   message with either a MoS IPv4 Address Option or a MoS Domain Name 
   List Option, the DHCP server MUST always construct the response
   according to the sub-option code(s) representing the service(s) 
   desired by the mobile node in the Sub-option Code field(s). Each 
   sub-option in response message may contain a list of one or more IP  

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   addresses or a list of one or more FQDNs of the MoS server hosting 
   the desired service. 

   In case that the server cannot find any Mobility Server satisfying 
   the requested Sub-opt Code, the server MUST return the MoS Option 
   with a sub-option by setting the Sub-opt Code to the requested
   Sub-opt Code and the length of the sub-option to 1.
 

  
6.2 Usage of MoS Options for DHCPv6  
    
   The requesting and sending of the proposed DHCPv6 options follow 
   the rules for DHCP options in [RFC3315]. 
    
6.2.1 Mobile node behavior 
    
   The mobile node may perform the MoS discovery either during initial 
   association with a network or when the mobility service is required.
   It may also try to perform the MoS discovery when it lacks the 
   network information for MoS or needs to change the  MoS for some 
   reasons, for instance, to recover from the single point of failure 
   of the existing MoS. 
   
   In order to discover the IP address or FQDN of a MoS, the mobile 
   node(DHCP client) MUST include either a MoS IPv6 Address Option 
   or a MoS Domain Name List Option into either a REQUEST or an  
   INFORMATION-REQUEST message. The inserted MoS Option MUST include 
   one or more sub-option(s) with the Sub-opt Code(s) that represents 
   the service(s) the mobile node is interested in.

6.2.2 DHCP Server behavior 
   
   When the DHCP Server receives either a REQUEST or an INFORMATION-
   REQUEST message with either a MoS IPv6 Address Option or a MoS 
   Domain Name List Option, the DHCP server MUST always construct 
   the response according to the sub-option code(s)representing the 
   service(s) desired by the mobile node in the Sub-option code 
   field(s). Each Sub-option in response message may contain a list 
   of one or more IP addresses or a list of one or more FQDNs of the 
   MoS server 
   hosting the desired service. 
   
   In case that the server cannot find any Mobility Server satisfying 
   the requested Sub-opt Code, the server MUST return the MoS Option 
   with a sub-option by setting the Sub-opt Code to the requested 
   Sub-opt Code and the length of the sub-option to 1. 

 

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7. Security Considerations 
    
   The security considerations in [RFC2131] apply. If an adversary 
   manages to modify the response from a DHCP server or insert its own 
   response, an MN could be led to contact a rogue Mobility Server, 
   possibly one that then would provide wrong information, event or 
   command for handover.  

   It is recommended to use either DHCP authentication option described 
   in [RFC3118] where available, or rely upon link layer security. 

   This will also protect the denial of service attacks to DHCP 
   servers. [RFC3118] provides mechanisms for both entity 
   authentication and message authentication. 
    

8. IANA Considerations 

   This document defines two new DHCPv4 options as described in Sections 
   2 and 3. 

   MoS IPv4 Address Option for DHCPv4 (OPTION-IPv4_Address-MoS)    TBA

   MoS Domain Name List option for DHCPv4 (OPTION-IPv4_FQDN-MoS)   TBA   
  
   This document creates a new registry for the Sub-Option fields in 
   the MoS DHCPv4 Address and FQDN options called the "IEEE 802.21
   Service Type" (Section 2 and 3).

      IS                       1
      CS                       2
      ES                       3  


  The values '0', '4' to '255' are reserved and MUST NOT be used. New
  values can be allocated by Standards Action or IESG approval.

  This document also defines two DHCPv6 options as described in 
  sections 4 and 5.

   MoS IPv6 Address Option for DHCPv6 (OPTION-IPv6_Address-MoS)   TBA

   MoS Domain Name List option for DHCPv6 (OPTION-IPv6_FQDN-MoS)  TBA   
   
   This document creates a new registry for the sub-option field in 
   the MoS DHCPv6 Address and FQDN options called the "IEEE 802.21 
   Service Type" (Section 4 and 5).

 
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        IS                       1
        CS                       2
        ES                       3
        
  The values '0', '4' to '65535' are reserved and MUST NOT be used. 
  New Values can be allocated via Standards Action as defined 
  in [RFC5226].
  
    
9. Acknowledgements 
    
   Authors would like to acknowledge the following individuals for 
   their valuable comments. 
   Alfred Hoenes, Bernie Volz, , David W. Hankins, Jari Arkko, 
   Telemaco Melia, Ralph Droms Ted Lemon Vijay Devarapalli,  and 
   Yoshihiro Ohba 


10. References

    10.1 Normative References 
        	
   [RFC1035] Mockapetris, P., "Domain names - implementation and 
      specification", STD 13, RFC 1035, November 1987. 

   [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 
      2131, March 1997. 

   [RFC3315] Dynamic Host Configuration Protocol for IPv6 (DHCPv6), 
      Droms et al, July 2003 

   [RFC3118] Authentication for DHCP Messages, Droms et al, June 2001 

   [RFC3396] Lemon, T. and S. Cheshire, "Encoding Long DHCP Options", 
      RFC3396, November 2002. 
    
   [RFC5226] T. Narten and H. Alvestrand, "Guidelines for Writing an 
    IANA  Considerations Section in RFCs" , May 2008. 
  
   [MSFD] T Melia, Ed., " Mobility Services Framework Design (MSFD)",
      draft-ietf-mipshop-mstp-solution-12.txt (Work in Progress).

   [MoS-DNS] Bajko, G., "Locating Mobility Servers",
      draft-ietf-mipshop-mos-dns-discovery-04.txt (Work in Progress), 


   10.2 Informative References 
    
   [IEEE802.21] IEEE 802.21 Standard for Local and Metropolitan Area 
      Networks: Media Independent Handover Services 

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Authors' Addresses 
    
   Gabor Bajko 
   Nokia 
   e-mail: gabor.bajko@nokia.com 

    
   Subir Das 
   Telcordia Technologies Inc.
   e-mail: subir@research.telcordia.com 
    




































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